Composite plasma modulator for plasma chamber

ABSTRACT

A plasma-processing apparatus includes a chamber, a plasma generator, and a composite plasma modulator. The chamber includes a plasma zone. The plasma generator is configured to generate a plasma in the plasma zone. The composite plasma modulator is configured to modulate the plasma. The composite plasma modulator includes a dielectric plate made of a first dielectric material and a first modulating portion made of a second dielectric material and coupled to the dielectric plate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Provisional Application Ser. No.62/430,401, filed on Dec. 6, 2016, the entire disclosure of which isincorporated herein by reference.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. Technological progress in IC manufacture has produced severalgenerations of ICs, and each generation fabricates smaller and morecomplex circuits than the previous generation. Dry etching is animportant method for fabrication of the semiconductor structures. Dryetching processes is used to remove material from the surface of thesemiconductor wafer. Etch uniformity measures the quality of the etchingprocess to evenly etch across the entire wafer. Maintaining uniformityacross the entire wafer is important to achieve desired performance ofthe semiconductor integrated circuit. However, as structures ofsemiconductor devices become more complex and/or the size of the waferbecome larger, conventional techniques have not been entirelysatisfactory in all respects.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a drawing schematically illustrating a plasma-processingapparatus according to various embodiments of the present disclosure.

FIG. 2 is a figure schematically showing the non-uniformity associatedwith critical dimensions (CDs) of a wafer after an etching processaccording to some comparative examples of the present disclosure.

FIG. 3 is a plan view schematically illustrating a composite plasmamodulator according to some embodiments of the present disclosure.

FIG. 4 is a cross-sectional view taken along line A-A′ in FIG. 3.

FIGS. 5A and 5B are cross-sectional views illustrating a compositeplasma modulator according to some embodiments of the presentdisclosure.

FIG. 6 is a plan view schematically illustrating a composite plasmamodulator according to yet some embodiments of the present disclosure.

FIG. 7 is a cross-sectional view taken along line B-B′ in FIG. 6.

FIGS. 8 and 9 are a cross-sectional view schematically illustrating acomposite plasma modulator according to yet some embodiments of thepresent disclosure.

FIG. 10 is plan view schematically illustrating a composite plasmamodulator according to yet some embodiments of the present disclosure.

FIG. 11 is a plan view schematically illustrating a composite plasmamodulator according to yet some embodiments of the present disclosure.

FIG. 12 is a drawing schematically illustrating a plasma-processingapparatus according to yet some embodiments of the present disclosure.

FIGS. 13A and 13B are drawings schematically illustrating application ofintended non-uniform plasma strength in semiconductor manufacturing.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

The present disclosure relates generally to a composite plasma modulatorfor a plasma chamber and a plasma-processing apparatus having thecomposite plasma modulator. The plasma-processing apparatus may be anyapparatus using plasma as working medium for manufacturing semiconductordevices. In some aspects of the present disclosure, theplasma-processing apparatus disclosed herein may improve the uniformityof processes by modulating the distribution of the plasma energy orplasma strength in the plasma chamber. In yet some aspects, however, theplasma-processing apparatus may provide an intended non-uniformdistribution for intended purposes. Various embodiments of the presentdisclosure will be described in detail hereinafter.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the embodiments. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus 100 may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein may likewise be interpreted accordingly.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

FIG. 1 is a drawing schematically illustrating a plasma-processingapparatus 100 according to various embodiments of the presentdisclosure. In some embodiments, the plasma-processing apparatus 100 maybe a plasma etching apparatus such as for example a capacitively coupledplasma (CCP) etching apparatus, a reactive ion etching apparatus, orother etching apparatuses using plasma as etchant. In yet someembodiments, the plasma-processing apparatus 100 may be a depositionapparatus such as for example a sputtering apparatus, or other physicalvapor deposition apparatuses. In addition, the plasma-processingapparatus 100 may be a cleaning apparatus, or other apparatuses usingplasma as working medium.

As illustrated in FIG. 1, the plasma-processing apparatus 100 includes achamber 110. The chamber 110 includes chamber wall 111 which encircles aplasma zone 113 therein. According to some embodiments of the presentdisclosure, the chamber 110 may be connected to a gas-supply source (notshown in FIG. 1), which is configured to supply a source gas into thechamber 110 for generating plasma. Illustrative examples of the gasinclude argon (Ar), helium (He), neon (Ne), oxygen (O₂), carbontetrafluoride (CF₄), nitrogen trifluoride (NF₃), dichlorodifluoromethane(CCl₂F₂), borane chloride (BCl₃), carbon tetrachloride (CCl₄), silane(SH₄), and the like, and a combination thereof. In some embodiments, thechamber 110 may be connected to a pump (not shown in FIG. 1) forevacuating the process gas and controlling the pressure in the chamber110.

A plasma generator 120 is included in the plasma-processing apparatus100, and is configured to generate plasma in the plasma zone 113 of thechamber 110. In some embodiments, the plasma generator 120 include aspiral coil 121, which may be coupled to a RF power source 123. Thespiral coil 121 may be energized by the RF power source 123 andtherefore generates an electrical field 125. The electric field 125causes dissociation of the gas in the chamber 110 so to form ions,radicals, and electrons. The generated electrons are accelerated by theelectric field 125 and strike gas molecules that causes the gasmolecules to be ionized. This process continues, and eventually plasmais generated and self-sustained in the plasma zone 113 of the chamber110. In some embodiments, a matching network 127 is optionally providedbetween the spiral coil 121 and the RF power source 123 in order tomatch impedances and increase efficiency.

The plasma-processing apparatus 100 may optionally includes an electrode130, over which a work piece 105 may be disposed. The electrode 130 iscoupled to a RF power source 133, and may also be referred to as a biaselectrode. The electrode 130 is configured to direct the ions in theplasma towards the work piece 105. When the plasma-processing apparatus100 is an etching apparatus, the work piece 105 may include asemiconductor substrate such as for example a silicon wafer.Alternatively, when the plasma-processing apparatus 100 is a sputteringapparatus, the work piece 105 may be a sputtering target. In addition, amatching network 137 may be optionally provided between the electrode130 and the RF power source 133 in order to match impedances andincrease efficiency. A heating plate 135 may be optionally integrated tothe electrode 130 for heating the work piece 105. Further, the heatingplate 135 may be coupled to a temperature controller 139 for controllingthe temperature of the heating plate 135.

In some aspects of the present disclosure, it has been discovered thatthe uniformity of the plasma influences the uniformity of etchingprocesses and/or deposition processes. Specifically, the distributionsof the energy of plasma ions may dominate the uniformity of the etchingrate and/or deposition. However, local effects of the apparatus 100,such as the geometry and size of the chamber 110 and the arrangement ofthe spiral coil 121, cause the non-uniformity in certain regions of theplasma zone 113. The non-uniform plasma causes several process issues,and decreases the manufacturing yield. FIG. 2 is a figure schematicallyshowing the non-uniformity associated with critical dimensions (CDs) ofa wafer after an etching process according to some comparative examplesof the present disclosure. It can be observed in FIG. 2 that the CDvalues in the central region R1 are considerably greater than that inthe region R2 around the perimeter of the wafer. Accordingly, in someaspects, the plasma-processing apparatus 100 disclosed herein mayimprove the uniformity of processes by modulating the distribution ofthe plasma energy. In yet some aspects of the present disclosure,however, the plasma-processing apparatus 100 may provide an intendednon-uniform distribution of the plasma energy to compensate thenon-uniformity of a certain layer formed in previous processes, and thatis described in detail hereinafter.

Referring back to FIG. 1, the plasma-processing apparatus 10 furtherincludes a composite plasma modulator 200, which is configured tomodulate the plasma in the chamber 110. In some embodiments, thecomposite plasma modulator 200 may be disposed between the plasmagenerator 120 and the plasma zone 113 of the chamber 110. For example,the composite plasma modulator 200 may be coupled to or mounted on thechamber wall 115 of the chamber 110 adjacent to the plasma generator 120(e.g., spiral coil 121). However, in yet some example, the compositeplasma modulator 200 may be positioned in or out of the chamber 110where it is able to modulate the plasma in the chamber 110. In yet someembodiments, the composite plasma modulator 200 is opposite to theelectrode 130. The composite plasma modulator 200 includes a pluralityof dielectric portions. The energy of the plasma ions can be influencedby the dielectric portions and therefore the distribution of energy ofthe plasma ions may be managed and/or modulated by the composite plasmamodulator 200. Various embodiments of the composite plasma modulator 200are discussed hereinafter with reference to FIGS. 3-11.

FIG. 3 is a plan view schematically illustrating the composite plasmamodulator 200 according to some embodiments of the present disclosure.FIG. 4 is a cross-sectional view taken along line A-A′ in FIG. 3. Thecomposite plasma modulator 200 includes a substrate 210 and a modulatingportion 220.

The substrate 210 includes a first dielectric material. Illustrativeexamples of the first dielectric material include quartz, ceramicmaterials, the like, and a combination thereof. Other examples of thefirst dielectric material include SiO₂, Si₃N₄, Al₂O₃, Y₂O₃, TiO₂, HfO₂,ZrO₂, Si, Ta₂O₅, La₂O₃, SrTiO₃, ZrSiO₄, HfSiO₄, the like, and acombination thereof. In some embodiments, the substrate 210 may have acircular contour. The substrate 210 may have other shapes or contours,rather than the illustrated circular shape, in accordance with yet someembodiments of the present disclosure. For example, the substrate 210may be a dielectric plate, dielectric disk, or dielectric ring made ofthe first dielectric material.

The modulating portion 220 includes a second dielectric material, whichis different from the first dielectric material of the substrate 210.The band gap of the second dielectric material of the modulating portion220 is different from the band gap of the first dielectric material ofthe substrate 210. In some embodiments, the second dielectric materialof the modulating portion 220 has a band gap ranged from about 0.5 eV toabout 10 eV. In some examples, the band gap of the second dielectricmaterial may be ranged about 4 eV to about 10 eV, such as about 5 eV,about 6 eV, about 7 eV, about 8 eV and about 9 eV. In yet some examples,the band gap of the second dielectric material may be ranged about 0.5eV to about 5 eV, such as about 0.8 eV, about 1 eV, about 2 eV, about 3eV and about 4 eV. It is noted that the band gap of the seconddielectric material of the modulating portion 220 may be greater or lessthan the band gap of the first dielectric material of the substrate 210.For example, when the band gap of the first dielectric material of thesubstrate 210 is ranged from 5 eV to 6 eV, the band gap of the seconddielectric material may be in the range of 0.5-4.5 eV or in the range of6.5-10 eV.

The dielectric material of the composite plasma modulator 200 affectsthe energy of the plasma ions in the chamber 110. In some embodiments,it has been observed that the energy of plasma ions in the plasma zone113 decreases when the band gap of the dielectric material is increased.For example, when the band gap of the modulating portion 220 is greaterthan the band gap of the substrate 210, the energy of the plasma ions inthe region corresponding to modulating portion 220 may be decreased.Therefore, the modulating portion 220 may compensate and/or modulate thenon-uniformity of the energy of plasma ions caused by the geometry ofthe chamber 110 or the arrangement of the spiral coil 121. The compositeplasma modulator 200 modulate the plasma by the arrangement of differentdielectric materials, and the composite plasma modulator 200 is free ofbeing connection to a voltage source in accordance with someembodiments.

In yet some embodiments, the second dielectric material of themodulating portion 220 has a dielectric constant ranged from about 1.5to about 100. The dielectric constant of the second dielectric materialof the modulating portion 220 may be greater or less than the band gapof the first dielectric material of the substrate 210. In some examples,the dielectric constant of the second dielectric material may be rangedfrom about 1.5 to about 16, such as about 2, about 2.5, about 3.0, about4, about 9, and about 13. In yet some examples, the dielectric constantof the second dielectric material may be ranged about 15 to about 100,such as about 20, about 25, about 30, about 40, about 60, about 80, andabout 90.

Illustrative examples of the second dielectric material of themodulating portion 220 include SiO₂, Si₃N₄, Al₂O₃, Y₂O₃, TiO₂, HfO₂,ZrO₂, Si, Ta₂O₅, La₂O₃, SrTiO₃, ZrSiO₄, HfSiO₄, the like, and acombination thereof. In some embodiments, the modulating portion 220consists essentially of the second dielectric material.

The modulating portion 220 is coupled to the substrate 210. In someembodiments, the modulating portion 220 is embedded in the substrate210, as shown in FIG. 4. In yet some embodiments, the modulating portion220 may be disposed on a surface of the substrate 210. In particular,the modulating portion 220 may be disposed on and in direct contractwith the surface of the substrate 210 facing the plasma zone 113 or thesurface facing the plasma generator 120 (e.g., spiral coil 121).

In some embodiments, the modulating portion 220 is substantially locatedat a center of the composite plasma modulator 200 to compensate thenon-uniformity of the plasma in the central region. As an example,referring to FIG. 2, when a relatively greater etching rate is presentedat the central region, the modulating portion 220 may be arranged at thecenter of the composite plasma modulator 200. In this case, themodulating portion 220 has a band gap greater than that of the substrate210. The etching rate in the central region may be reduced because theenergy of the plasma ions in this region is reduced due to themodulating portion 220. Therefore, the non-uniform etching rate may becompensate and adjusted by the composite plasma modulator 200. In someexamples, the modulating portion 220 may have a circular contour, asshown in FIG. 3.

Referring to FIGS. 5A and 5B, the modulating portion 220 may be moveablerelative to the substrate 210 of the composite plasma modulator 200 inaccordance with some embodiments. The modulating portion 220, forexample, is moveable along a direction perpendicular to a surface 211 ofthe substrate 210. As shown in FIG. 5A, the modulating portion 220 maybe moved towards the work piece 105 (e.g., silicon wafer) while thesubstrate 210 of the composite plasma modulator 200 is fixed.Alternatively, as shown in FIG. 5B, the modulating portion 220 may bemoved far away from the work piece 105 (e.g., silicon wafer). Theadjustable displacement of the modulating portion 220 can increase ordecrease the energy of the plasma ions in the local region correspondingto the modulating portion 220, depending upon the material of themodulating portion 220. In the embodiments where the band gap of themodulating portion 220 is greater than the substrate 210, the energy ofthe plasma ions in the corresponding region may be further decreasedwhen the modulating portion 220 is moved towards the plasma zone 113. Insome embodiments, the composite plasma modulator 200 may further includean adjustment mechanism 215 configured to adjust the displacement and/orposition of the modulating portion 220 in the composite plasma modulator200. In yet some embodiments, the thickness T1 of the modulating portion220 is greater than the thickness T2 of the substrate 210. For example,the thickness T1 of the modulating portion 220 may be about 1 mm toabout 30 mm.

FIG. 6 is a plan view schematically illustrating a composite plasmamodulator 200 a according to yet some embodiments of the presentdisclosure. FIG. 7 is a cross-sectional view taken along line B-B′ inFIG. 6. The composite plasma modulator 200 includes a dielectric plate210 a and a number of modulating portions, such as a first modulatingportion 220, a second modulating portion 230, a third modulating portion240, and a fourth modulating portion 250. The first, second, third, andfourth modulating portions 220, 230, 240, 250 are disposed on a surface211 a of the dielectric plate 210 a. Particularly, the first modulatingportion 220 is surrounded by the second modulating portion 230, which issurrounded by third modulating portion 240. Further, the fourthmodulating portion 250 is arranged to encircle the first, second, andthird modulating portions 220, 230, 240. In some embodiments, the firstmodulating portion 220 has a circular shape, whereas each of the second,third, and fourth modulating portions 230, 230, 240 has an annularcontour.

In addition, the first, second, third, and fourth modulating portions220, 230, 240, 250 respectively include a first, second, third, andfourth dielectric material, and each of the modulating portions 220,230, 240, 250 has a dielectric constant and a band gap. The dielectricconstant and/or band gap of one of the modulating portions 220, 230,240, 250 is different form that of another one of the modulatingportions 220, 230, 240, 250. In some embodiments, the dielectricconstants and/or band gaps of the first, second, third, and fourthdielectric materials are different from each other. The arrangement ofthe dielectric constants and/or band gaps of these dielectric materialsmay be varied in a variety of manners for different purposes. Forexample, the arrangement of the modulating portions 220, 230, 240, 250may be used to eliminate the non-uniformity of the plasma strengthcaused by local effect of the processing chamber.

In some embodiments, the band gaps of the first, second, third, andfourth dielectric materials are sequentially increased from the firstmodulating portion 220 to the fourth modulating portion 250. In yet someembodiments, the band gaps of the first, second, third, and fourthdielectric materials may be sequentially decreased from the firstmodulating portion 220 to the fourth modulating portion 250. In yet someembodiments, any one of the modulating portions 220, 230, 240, 250 mayhave the maximal or minimal dielectric constant (or band gap) amongthese modulating portions 220, 230, 240, 250.

In some embodiments, at least one of the modulating portions 220, 230,240, 250 has a dielectric constant greater than the dielectric constantof the dielectric plate 210 a, whereas another one of the modulatingportions 220, 230, 240, 250 has a dielectric constant less than thedielectric constant of the dielectric plate 210 a. In some embodiments,the dielectric constants and/or band gaps of all of the first, second,third, and fourth dielectric materials are different from that ofdielectric plate 210 a.

Further, not all of the modulating portions 220, 230, 240, 250 areneeded, and any one of the modulating portions 220, 230, 240, 250 may beremoved or omitted. For example, the central modulating portions 220 maybe omitted, leaving the annular modulating portions 230, 240, 250.Alternatively, the modulating portions 230, 250 may be omitted, leavingthe modulating portions 220, 240.

The band gaps of the modulating portions 220, 230, 240, 250 are in therange from about 0.5 eV to about 10 eV, in accordance with someembodiments. In some examples, the band gap of the modulating portions220, 230, 240, 250 may be ranged about 4 eV to about 10 eV, such asabout 5 eV, about 6 eV, about 7 eV, about 8 eV and about 9 eV. In yetsome examples, band gaps of the modulating portions 220, 230, 240, 250may be about 0.5 eV to about 5 eV, such as about 0.8 eV, about 1 eV,about 2 eV, about 3 eV and about 4 eV.

The dielectric constant of the modulating portions 220, 230, 240, 250are in the range from about 1.5 to about 100, in accordance with someembodiments. In some examples, the dielectric constant of the seconddielectric material may be about 1.5 to about 16, such as about 2, about2.5, about 3.0, about 4, about 9, and about 13. In yet some examples,the dielectric constant of the second dielectric material may be rangedabout 15 to about 100, such as about 20, about 25, about 30, about 40,about 60, about 80, and about 90.

FIG. 8 is a cross-sectional view schematically illustrating a compositeplasma modulator 200 b according to yet some embodiments of the presentdisclosure. The plane view of the composite plasma modulator 200 b maybe the same as that depicted in FIG. 6. The composite plasma modulator200 b includes a number of modulating portions 220 b, 230 b, 240 b, 250b. The modulating portions 220 b, 230 b, 240 b, 250 b are moveablerelative to each other. Two adjacent ones of the modulating portions 220b, 230 b, 240 b, 250 b are engaged with each other. In examples, themodulating portions 220 b, 230 b, 240 b, 250 b respectively include afirst, a second, a third, and a fourth dielectric material, and each ofthe modulating portions 220 b, 230 b, 240 b, 250 b has a dielectricconstant and a band gap. The dielectric constant and/or band gap of oneof the modulating portions 220 b, 230 b, 240 b, 250 b is different formthat of another one of the modulating portions 220 b, 230 b, 240 b, 250b. In some embodiments, the dielectric constants and/or band gaps of themodulating portions 220 b, 230 b, 240 b, 250 b are different from eachother. The modulating portions 220 b, 230 b, 240 b, 250 b are moveabletowards or far away from the plasma zone 113, and the energy of plasmaions may be modulated by the displacement of the modulating portions 220b, 230 b, 240 b, 250 b. The adjustable displacement of the modulatingportions 220 b, 230 b, 240 b, 250 b can independently fine tune theenergy of the plasma ions in the respective regions corresponding to themodulating portions 220 b, 230 b, 240 b, 250 b. Therefore, the compositeplasma modulator 200 b having the moveable modulating portions 220 b,230 b, 240 b, 250 b may be adapted to different processes. For example,as shown in FIG. 8, the modulating portions 220 b, 230 b, 240 b, 250 bmay be adjusted in an axis direction D such that the composite plasmamodulator 200 b has a step-liked bottom surface. The modulating portion220 b at the center of the composite plasma modulator 200 b is moved toa position that is farthest away from the work piece 105, whereas themodulating portion 250 b at the periphery of the composite plasmamodulator 200 b is moved to a position that is nearest to the work piece105. The configuration shown in FIG. 8, for example, may be adapted to aprocess chamber with a sequentially-changed concentric non-uniformity.Alternatively, as illustrated in FIG. 9, the modulating portions 220 b,230 b, 240 b, 250 b may be move to another configuration for adapting toanother process chamber with an intermittent annular non-uniformity.

FIG. 10 is plan view schematically illustrating a composite plasmamodulator 200 c according to yet some embodiments of the presentdisclosure. The composite plasma modulator 200 c includes a dielectricdisk 210 c and a plurality of first modulating blades 260 coupled to thedielectric disk 210 c. The first modulating blades 260, for example, maybe disposed on the surface 211 c of the dielectric disk 210 c whichadjacent to the plasma zone of the chamber. The first modulating blades260 are configured to modulate the energy of the plasma ions in thechamber. Each of the first modulating blades 260 includes a dielectricmaterial different from a dielectric material of the dielectric disk 210c. Therefore, each of the first modulating blades 260 has a dielectricconstant (and/or band gap) different from that of the dielectric disk210 c. As shown in FIG. 9, each of the first modulating blades 260 mayextend from a center of the dielectric disk 210 c to a position within(or alternatively out of) the dielectric disk 210 c, along a radialdirection of the dielectric disk 210 c. In some embodiments, eachmodulating blade 260 has an end 261 adjacent to the center of thedielectric disk 210 c and an opposite end 262 adjacent to the peripheryof the dielectric disk 210 c. The width W1 of the end 261 is less thanthe width W2 of the opposite end 262. In some embodiments, eachmodulating blade 260 has a sector or triangular shape, and the length ofeach first modulating blade 260 is substantially equal to the radius ofthe dielectric disk 210 c.

In yet some embodiments, the composite plasma modulator 200 c furtherincludes a plurality of second modulating blades 270. Each of the secondmodulating blades 270 includes a dielectric material different from thedielectric material of the first modulating blades 260. Therefore, eachof the first modulating blades 260 has a dielectric constant (and/orband gap) different from that of the first modulating blades 260.Further, each of the second modulating blades 270 may extend from thecenter of the dielectric disk 210 c to a position within the dielectricdisk 210 c, along the radial direction of the dielectric disk 210 c. Thelength of each second modulating blade 270 may be less than the lengthof each first modulating blade 260. In some examples, each secondmodulating blade 260 has a sector or triangular shape.

The first modulating blades 260 and the second modulating blades 270 areextended on an identical level, in accordance with some embodiments. Forexample, the first and second modulating blades 260, 270 may extend onthe same surface 211 c of the dielectric disk 210 c. In some examples,each second modulating blade 270 are arranged between two adjacent firstmodulating blades 260. The thickness of each second modulating blade 270may be greater or less than the thickness of each first modulating blade260.

The first and second modulating blades 260, 270 are rotatable withrespect to the dielectric disk 210 c, in accordance with someembodiments. In particular, each of the first and the second modulatingblades 260, 270 may be rotated in a clockwise direction (or counterclockwise direction), as illustrated by arrow F in FIG. 9. In examples,a joint structure 275 may be provided to joint first and the secondmodulating blades 260, 270 with the dielectric disk 210 c. For instance,the joint structure 275 may be a pivot at the center of the dielectricdisk 210 c such that the first and second modulating blades 260, 270 arepivotally connected to the dielectric disk 210 c.

FIG. 11 is a plan view schematically illustrating a composite plasmamodulator 200 d according to yet some embodiments of the presentdisclosure. The composite plasma modulator 200 d includes a dielectricplate 210 d and one or more quadrangular modulating portions 280. Thequadrangular modulating portions 280 include a dielectric materialdifferent from the dielectric material of the dielectric plate 210 d.The dielectric constant (or band gap) of the quadrangular modulatingportions 280 may be greater or less than the dielectric constant (orband gap) of the dielectric plate 210 d. Therefore, the energy of plasmaions mat be locally modulated by the quadrangular modulating portions280. The quadrangular modulating portions 280 are detachably fixed ormounted on the dielectric plate 210 d. In some embodiments, thedielectric plate 210 d includes a plurality of holding structures suchas for example clamping structures 213 and/or catches 214 for detachablyfixing the quadrangular modulating portions 280 onto the dielectricplate 210 d.

The quantity and the arrangement of the quadrangular modulating portions280 can be varied to fit for different characteristics of variousprocessing chambers. As illustrated in FIG. 11, the composite plasmamodulator 200 d may be aligned with the work piece 105 in someembodiments. Each of quadrangular modulating portions 280 may be sizedto fit for one of the fields or dies of the work piece 105. Therefore,the plasma strength corresponding to each field or die of the work piece105 may be individually managed and modulated by the arrangements of thequadrangular modulating portions 280. For example, while non-uniformityis present at region R of the work piece 105, the quadrangularmodulating portions 280 may be disposed at the corresponding area of thecomposite plasma modulator 200 d, and thereby the non-uniformity may besuppressed or improved. Further, different processing chamber probablyhave different non-uniformity patterns, and the composite plasmamodulator 200 d disclosed herein can be adapted to various processingchambers.

In yet some embodiments, the composite plasma modulator 200 d furtherincludes a plurality of quadrangular modulating portions 290, whichinclude a dielectric material different from the dielectric materials ofthe dielectric plate 210 d and the quadrangular modulating portions 280.In some examples, the dielectric constant of each quadrangularmodulating portion 290 is greater than the dielectric constant of thedielectric plate 210 d, whereas the dielectric constant of eachquadrangular modulating portions 280 is less than the dielectricconstant of the dielectric plate 210 d. In yet some examples, thedielectric constant of the quadrangular modulating portions 290 isranged between the dielectric constant of the dielectric plate 210 d andthe dielectric constant of the quadrangular modulating portions 280.

FIG. 12 illustrates a plasma-processing apparatus 100 a in accordancewith yet some embodiments of the present disclosure. Theplasma-processing apparatus 100 a is similar in structure to theplasma-processing apparatus 100 shown in FIG. 1, except that theplasma-processing apparatus 100 a further includes a slot shell 140. Theslot shell 140 is adjacent to a chamber wall 115, and a slot 142 ispresent in the slot shell 140. The slot 142 is configured to accommodatethe composite plasma modulator disclosed in the present disclosure, suchas for example composite plasma modulators 200, 200 a, 200 b, 200 c, 200d. In some embodiments, the slot shell 140 may has a bottom plate 144fastened to the chamber wall 115, and the slot 142 is located over thebottom plate 144. The composite plasma modulator may be inserted intothe slot 142, or be taken out from the slot 142. While theplasma-processing apparatus 100 a exhibits different non-uniformitypatterns in different processes, a suitable composite plasma modulatormay be used and inserted into the slot 142 to rectify thenon-uniformity.

Although a number of embodiments described hereinbefore are described ina manner of improving the uniformity of plasma strength, theplasma-processing apparatus and composite plasma modulator disclosedherein may be used to provide an intended non-uniform plasma strength.FIGS. 13A and 13B are drawings schematically illustrating application ofintended non-uniform plasma strength in semiconductor manufacturingprocesses. As a layer formed on a wafer has a non-uniform thickness, anetching process with complementary distribution of etching rate may beprovided to rectify the non-uniformity of thickness by using thecomposite plasma modulator disclosed herein. For example, as illustratedin FIG. 13A, when the layer 150 a has a maximal thickness at the centralregion of the wafer 160, the distribution of etching rate 170 a may bemodulated to have a maximal etching rate at the central region.Therefore, the non-uniformity of thickness may be rectified. On theother hand, as illustrated in FIG. 13B, when the layer 150 b has aminimal thickness at the central region of the wafer 160, thedistribution of etching rate 170 b may be modulated to have a minimaletching rate at the central region. Accordingly, the non-uniformity ofthe layer(s) or structure(s) formed in previous processes may berectified in the subsequent processes. The composite plasma modulatorand the apparatus disclosed herein may provide a desired distribution ofplasma strength in various plasma-processing chambers such as forexample etching chambers and deposition chambers.

In accordance with one aspect of some embodiments, a composite plasmamodulator for a plasma chamber is provided. The composite plasmamodulator includes a substrate and a first modulating portion. Thesubstrate includes a first dielectric material. The first modulatingportion includes a second dielectric material and is coupled to thesubstrate. The first dielectric material is different from the seconddielectric material.

In accordance with another aspect of some embodiments, aplasma-processing apparatus includes a chamber, a plasma generator, anda composite plasma modulator. The chamber includes a plasma zone. Theplasma generator is configured to generate a plasma in the plasma zone.The composite plasma modulator is configured to modulate the plasma. Thecomposite plasma modulator includes a dielectric plate made of a firstdielectric material and a first modulating portion made of a seconddielectric material and coupled to the dielectric plate.

In accordance with another aspect of some embodiments, aplasma-processing apparatus includes a chamber, a plasma generator, acomposite plasma modulator, and an electrode. The chamber includes aplasma zone. The plasma generator is configured to generate a plasma inthe plasma zone. The composite plasma modulator is disposed between theplasma generator and the plasma zone. The composite plasma modulatorincludes a first dielectric portion made of a first dielectric materialand a second dielectric portion made of a second dielectric material.The second dielectric portion is coupled to the first dielectricportion. The electrode is opposite to the composite plasma modulator.

What is claimed is:
 1. A composite plasma modulator for a plasmachamber, the composite plasma modulator comprising: a substratecomprising a first dielectric material; and a first modulating portioncomprising a second dielectric material and coupled to the substrate,wherein the first dielectric material is different from the seconddielectric material.
 2. The composite plasma modulator according toclaim 1, wherein the first modulating portion has a circular contour,and is substantially located at a center of the composite plasmamodulator in a plan view.
 3. The composite plasma modulator according toclaim 1, wherein the first modulating portion has an annular contour. 4.The composite plasma modulator according to claim 1, wherein thesubstrate has a circular contour, and the first modulating portioncomprises a plurality of blades, wherein each of the blades extends froma center of the substrate to a position within the substrate along aradial direction of the substrate in a plan view.
 5. The compositeplasma modulator according to claim 1, further comparing a secondmodulating portion made of a third dielectric material and coupled tothe substrate.
 6. The composite plasma modulator according to claim 5,wherein the second modulating portion surrounds the first modulatingportion.
 7. The composite plasma modulator according to claim 6, thefirst modulating portion has a circular contour, and the secondmodulating portion has an annular contour.
 8. The composite plasmamodulator according to claim 6, the first modulating portion has a firstannular contour, and the second modulating portion has a second annularcontour.
 9. The composite plasma modulator according to claim 5, whereinthe first modulating portion comprises a plurality of first blades, andthe second modulating portion comprises a plurality of second blades,wherein each of the first and second blades extends from a center of thesubstrate to a position within the substrate along a radial direction ofthe substrate in a plan view.
 10. The composite plasma modulatoraccording to claim 5, wherein the first modulating portion comprises aplurality of first quadrangular portions, and the second modulatingportion comprises a plurality of second quadrangular portions, whereineach first quadrangular portion is made of the second dielectricmaterial, and each second quadrangular portion is made of the thirddielectric material.
 11. The composite plasma modulator according toclaim 1, wherein the second dielectric material of the first modulatingportion has a dielectric constant ranged from about 1.5 to about 100.12. The composite plasma modulator according to claim 1, wherein thesecond dielectric material of the first modulating portion has a bandgap ranged from about 0.5 eV to about 10 eV.
 13. The composite plasmamodulator according to claim 1, wherein the second dielectric materialof the first modulating portion comprises SiO₂, Si₃N₄, Al₂O₃, Y₂O₃,TiO₂, HfO₂, ZrO₂, Si, Ta₂O₅, La₂O₃, SrTiO₃, ZrSiO₄, HfSiO₄, or acombination thereof.
 14. The composite plasma modulator according toclaim 1, wherein the first modulating portion is moveable relative tothe substrate.
 15. A plasma-processing apparatus, comprising: a chambercomprising a plasma zone; a plasma generator configured to generate aplasma in the plasma zone; and a composite plasma modulator configuredto modulate the plasma, wherein the composite plasma modulatorcomprises: a dielectric plate made of a first dielectric material; and afirst modulating portion made of a second dielectric material andcoupled to the dielectric plate.
 16. The plasma-processing apparatusaccording to claim 15, wherein the composite plasma modulator isdisposed between the plasma generator and the plasma zone.
 17. Theplasma-processing apparatus according to claim 15, further comprising aslot shell adjacent to a chamber wall of the chamber, wherein a slot ispresent in the slot shell, and the slot is configured to accommodate thecomposite plasma modulator.
 18. The plasma-processing apparatusaccording to claim 15, wherein the composite plasma modulator furthercomprises a second modulating portion made of a third dielectricmaterial and coupled to the dielectric plate, wherein at least one ofthe first and third dielectric material has a dielectric constant rangedfrom about 1.5 to about
 100. 19. The plasma-processing apparatusaccording to claim 15, wherein the first modulating portion is moveablerelative to the dielectric plate.
 20. A plasma-processing apparatus,comprising: a chamber comprising a plasma zone; a plasma generatorconfigured to generate a plasma in the plasma zone; a composite plasmamodulator between the plasma generator and the plasma zone, wherein thecomposite plasma modulator comprises a first dielectric portion made ofa first dielectric material and a second dielectric portion made of asecond dielectric material, the second dielectric portion being coupledto the first dielectric portion; and an electrode opposite to thecomposite plasma modulator.